Class to check object before instantiating

[grob115]

Hi, have a class similar to the following to create objects of vehicles. However, I want to ensure to have the object for a car to be instantiated only once (don't want two objects created for the same car), what is the best approach in ensuring this is the case?

Class CVehicle {
char * license; // vehicle license plate
char * make; // vehicle manufacturer
char * model; // vehicle model name

public:
CVehicle (char * license, char * make, char * model) {
this.license = license;
this.make = make;
this.model = model;
}
}